Ignition coil cassettes used for automotive applications are constructed of plastic with epoxy potting, and include metallic bushings through which mounting bolts pass for mounting the ignition coil cassette to a mounting surface.
As shown at FIGS. 1 through 3, the current practice is to provide an automotive engine ignition coil cassette 10 with metallic bushings 12 therefor. The bushings 12 have an irregularity 14, such as a knurl, a hole, or an undercut 14′ for being anchored relative to the casing by interfacing with plastic. The bushings 12 are, according to one methodology of the prior art, overmolded with plastic 16 seatably into a cylindrical bushing seat 18 which is coextensive with the bushing. Alternatively according to a second methodology of the prior art, the bushings 12 are ulrasonically inserted by pressing into position at the respective bushing seats 18.
Plastic overmolding of the bushing represents an expensive extra production step. On the other hand, ultrasonic insertion, while eliminating the plastic overmolding step, can potentially cause damage to the ignition coil cassette.
Accordingly, what is needed is a process by which bushings may be installed into an ignition coil cassette without the cost associated with the plastic overmolding installation process, and without the potential for damage associated with the ultrasonic insertion process.